In September 1967, Presley was at a low ebb. He was still hitting the Top 40, but his hits were flabby, formulaic songs from his flabby, formulaic movies (which weren’t hits at all). According to Peter Guralnick’s definitive biography of Elvis’ later years, “Careless Love,” Presley had taken a shine to a middling hit by Reed, “Guitar Man.”

But the crack Nashville studio crew couldn’t get the sound Elvis was looking for, and so the call was put out for Reed himself. Here’s Guralnick: “It soon became apparent that there was no way they were going to get the Jerry Reed sound without Jerry Reed himself. … When he arrived, he looked, said [producer] Felton [Jarvis], ‘like a sure-enough Alabama wild man. You know, he hadn’t shaved in about a week, and he them old clogs on - that was just the way he dressed. He come in and Elvis looked at him and said, “Lord, have mercy, what is that!” ’ ”

What “that” was, was the sound of Elvis’ new record, “the kind of churning, driving rhythm that has characterized Elvis’ music from the first,” writes Guralnick. Because of a publishing snafu, “Guitar Man” wasn’t released until January 1968 and - surprisingly, in retrospect - peaked at just No. 43. But its Reed-penned follow-up, “U.S. Male,” cracked the Top 40, and - better still - “Guitar Man” gave the writers of a planned Elvis TV special something to put at the show’s center.

You know the rest: A rejuvenated Elvis put his all into the TV special, it aired December 3, 1968, and suddenly Elvis was hot again.

As Elvis sang in the special: “I’m gonna get myself back on the track / I’ll never, never ever look back / I’ll never be more than what I am / Wouldn’t you know / I’m a swinging little guitar man.”